rumors and conspiracy theories … are they funny when they don’t come true?
on 09/21/2007 at 09:32 PM
Don’t Panic!
(Thanks, Mr. Adams...)
Of course I can’t remember who it was, but one of the talk radio people discussed this on air. It turns out the massive ‘puts’ and ‘takes’ are simply ways of hedgeing some other form of investment and one then sells portions of the hedge. No, I don’t understand all the workings and probably don’t even remember this part quite right, but it’s a fairly routine and non-threatening sort of thing to do.
Please, I’m not discounting the need for a healthy paranoia of many things, but sometimes a backfire is just a backfire.
I have to ask, independent of the stock market or terrorist concerns… Just how fast a twist do you have in your .45 that you are concerned about over-spinning it and blowing it up?
I cannot forsee destroying a .45 - pistol or rifle = bullet by overspin unless the gun were rifled with a tap or something.
Are you aware this whole discussion derives from P. O. Ackley building a .219 Donaldson Wasp with a 1 in 5 twist? He was studying the effect of rifling on pressure curves. (Turns out it’s negligible.) His first shots came apart and he finally figured it out. Then he did some more fiddling and ended up with .224 bullets making .30 holes at 100 yards… He must have been an engineer, huh?
However, I’m interested in further development of the Greenhill Formula. I know velocity and ballistic coefficient have to fit in the reckoning somewhere. (My math is limited, I fear.)
Archie, right now one is 1-20, and the other is 1-14. But it’s getting to be time for a new barrel, and I’ve found .458 barrels with twists running from 1-10 to 1-22. The “little” 300 grain bullets are happy in the 1-20 at 2600fps (93,600rpm) but going to a 1-10 at the same velocity would push that up to 187,200rpm. That may be pushing or exceeding the yield strength limit of the jacket. A 1-14 or a 1-12 twist could be a safe choice.
Faster twist limits precession, and it enhances straight-line penetration and expansion. I’m part of the camp that says that “overstabilization” is a myth for any real-world situation; maybe it applies to the 1000 yard paper punchers but nobody else.
Given that many of the available bullets in this caliber (Woodleigh, A-Square, Northern Technologies, etc) are damned tough, anything that would help them mushroom more would be a good thing. Conversely, almost all of the lighter .458 bullets are very lightly constructed, and designed for the low velocities generated by blackpowder .45-70s. Spin them too fast and they will shred. Same goes for cast lead alloy bullets until the BHN gets way up there. So it’s a balance point I’m trying to find. Given the price rise of ammo components over the past two years, cast bullets and bulk jacketed 300-350 grainers are starting to look very appealing.
No, I didn’t know that about Ackley, but it figures. He was the master. I’ve heard from many sources that engraving and spinning a bullet uses about 5% of the powder’s energy, regardless of twist rate.
If you have a copy of the A-Square load manual, read Alphin’s comparison of his .500 A-Square against the .460 Weatherby. The .500 has nearly double the penetration and that’s due entirely to the 1-10 twist ( the .460 is 1-16 ). Recall a number of cartridges that are famous for penetration (6.5x55 Swede, .375H&H, etc) and you’ll find that they all have a Penetration Stability Factor ( the bullet’s surface feet per second divided by the muzzle velocity, which works out to a constant ) of 9.5% or higher. Yes, most of them famously used bullets of very high SD too, but SD alone doesn’t do the job. Read all about that over at Ulf’s most excellent manifesto. We’ve exchanged a lot of emails, and he agrees with Alphin.
As you probably know, the Greenhill formula, which roughly calculates minimum required spin for a bullet flying in the air, now has a set of extra constants that take velocity into consideration. The formula was written as 150*diameter*diameter/bullet length, but these days 180 is a better constant. But all Greenhill gives you is the minimum. In air. And animals are at about 900 times denser than air ... so what I’m looking for is the upper limit, which is different for each bullet. So my idea is to figure out that upper limit for the weakest bullet I shoot at a given velocity, then choose a twist just slower than that. Or load it a tad slower. The nice guys at Badger Barrels will make me whatever I want, or I could go with Shilen who has the wide selection I alluded to at the beginning of this ramble. Either way it would still be cheaper to just go buy a new Marlin 1895 XLR, but that would be a practical solution and this is more a labor of love.
Yeah, I know, I could avoid the whole thing by just switching to the solid copper Barnes X bullets. They even have far superior BCs. Where’s the fun in that?
Exactly my point Anonymouse.
This may have been some form of innocuous hedging, but it was done with only 2 Puts, and they were of massive scale. So if they were hedging actions it would have to be on investments worth 10s of billions. Even the biggest of the enormous insurance companies, who have assests like you can’t believe (I used to go over their financial statements when I worked for an insurance rating service) usually only have 1 or 2 billion at the most, with a large percent tied up in long term muni bonds. So this rules them out, and most banks too, unless somehow they all got together and did a group move on the market. Unlikely. And very risky I would think. This kind of loss would sink just about any single company on earth, and tumble most governments if their people knew what was going on. So it does seem a bit on the tinfoil side, and that compass points to terrorist financing these days. Or drug cartel money.
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